Grinding machine



July 24,192 1,678,413

- \A. ZRHRI'NGER GRINDING MACHINE Filed Dec.22, 1926 4 Sheeiis-Sheet 1July 24, 1928, 1,618,413

A. ZKHRI NGER GRINDING MACHINE Filed Dec. 22, 1926 4 Sheets-Sheet 2 July24, 3928. 1,678,413

' A. ZAHRINGER GRINDING MACHINE Filed Dec. 22, 1926 4 Sheets-Sheet 3July 24, 1928. 1,678,413

A. ZAHRINGER GRINDING MACHINE Filed Dec. 22, 1926 4 Sheets-Sheet 4 \i sI 72 0 MW Patented July 24, 1928.

Si'l'ATES ALEXANDER ZAHRINGER, OF STUTTGART, GERMANY.

GRINDING MACHINE.

Application filed December 22, 1926, Serial No. 156,366, and in GermanyDecember 28, 19 25.

is applied to the grinding wheel at the beginning of the operation andthe drill is then turned so as to present gradually all points of thecutting edge'to the face of the grinding wheel. In this mannera suitableangle of relief may be obtained but the cutting edge will be curved.

In my machine, on the other hand, I gen erate a straight cutting edge byapplying the cutting edge to the face of the grinding Wheel for itsentire length and throughout the grinding operation.

To this end. I rock the support on which the drill is carried about anaxis which intersects the face of the grinding wheel at such an anglethat the cutting edge is fully applied to the face of the grindingwheel, and I rock this axis bodily about another axis which extends inthe face of the grinding wheel. This axis intersects the outer end ofthe cutting edge and by being rocked about the point of intersection thecutting edge is provided with the required relief while still applied tothe face of the grinding wheel throughout its length, and a straightcutting edge is obtained notwithstanding its being relieved.

In a preferred embodiment of my invention, I provide a support having ahinged flap. The axis of the hinge makes the said angle with the cuttingedge, thedrill is carried on the flap in a suitable chuck, the supportis carried on a bracket which is adapted to rock about the axis whichextends in the face of the grinding wheel and intersects the outer endof the cutting edge, and I so connect the flap and the bracket by a,preferably adjustable, mechanism that the bracket is rocked through apredetermined angle for any angle through which the flap is: rockedabout its hinge.

In the drawings affixed to this specification and forming part thereof amachine embodying my invention is illustrated diachuck limited by anabutment, not shown.

grammatically by way of example. In the drawings Fig. '1 is an elevationof the machine viewed in the direction of the central line of a drillinserted in its chuck,

Fig. 2 is a section on the line lT-lll of Fig. 1,

Fig. 3- is a detail showing the means for feeding the drill toward thegrinding wheel, Fig. at is a diagram illustrating the relative positionof the several axes and central lines of the system,

Fig. 5 is an elevation similar to Fig. 1 but viewed in the direction ofthe axis about which the drill is rocked by hand, and partly in sectiona ong the line IVIV in Fig. 2,

Fig. 6 is an elevation illustrating the mechanism for imparting rockingmotion about the axis in-the plane of the grinding wheel to the axisabout which the drill is rocked bodily, partlyin section on thelines VVand Vcz-Va in Fig. 1,

Fig. 7 is an end elevation of the chuck in which the drill is secured,

8 is an elevation showing one of the jaws separately,

Fig. 9 is an axial section of the grinding wheel showing its mode ofattachment to its shaft.

Referring now to the drawings, 1 is an outer bracket which is pivotallycarried in the frame 2 of the machine by means of lugs 8 and 4 so thatit may rock on said frame about an axis '7, as best seen in Fig. 2. Itsmotion with respect to the frame is 5 is an inner bracket which isfulcrumed in the bracket 1 by means of lugs 6 and 7 and pins which areinserted ,in corresponding lugs S and 9 of the bracket. The axis (Zconnecting these pins extends in the plane of the grinding wheel 10which is rotatably carried in the frame 2 and connected with a pulley 11towhich rotation may be imparted by any suitable means, not shown. Theangular relative displacement of the outer and inner brackets 1 and 5 islimited by an adjustable abutment 12 in 2. lug 13 of the inner bracket 5and a spring 14 holds the abutment engaged with the bracket 1, A table15 is cast integral with the inner bracket 5 and the lug 13 and tendshorizontally from the bracket as indicated, partly in dotted lines, in2; On this table a support 17 is carried to which a flap 18 is connectedby a hinge pin 19. The flap 18 carries the chuck 20 for the drill 21.The axis of the hinge is indicated at c and the central line of thedrill 21 is indicated at Z).

Referring now to Fig. 1, this shows diagrammatically the relativeposition of the several axes and the grinding wheel 10. c is the axis ofthe hinge pin 19 about whicl the drill 21 is rocked bodily with itschuck 20 on the flap 18. The axis makes an angle :1 with the face of thegrinding wheel 10. 0' is the axis about which the inner bracket isadapted to rock in the outer bracket 1. It will appear from Fig. 1 thattli -axis extends in the face of the grim wheel 10. The central line bof the drih makes an angle w ith the plane of the grindi.i wheel 10.

The distance 0 of the axis 0 from the axis (Z is varied in proportion tothe size of the drill by displacing the support on the table 15, as willbe do ere-ed and. i order to turn the area of the g ind'g wheel tobetter advantage the outer brac not. 1 may be rocked about the axis Ctis the axis of the grinding wheel which extends 111 parallel to the axisso that the angrposition of the central line Z) not var u when thebracket 1 is rocked about the axis It will appear from the diagram thatth cutting edge of the drill 21 is applied to thface of the grindingwheel for its entir length and that the axis (Z about which the edge isrocked for relieving, intersects the outer end of the cutting edge. Theopposite edge of the drill is ground in the same manner by reversing thechuck 20, will be described.

22 is a pin projecting from the lower face of the su 'iport 17 andextending through a slot 23 in the table 15. 2 1 is a nut on thethreaded. end of the pin 22 by which the support 17 may be clamped invarious positions on the table 15. A -'-.-:-:huped r'ilge 25 is formedon the table 15 which extends in parallel to the slot 23 and engages acorresponding groove in the lower face of the support 11. The relativeposition of the support- 17 and the table 15 is indicated by an index 26on the part 17 and a graduation 28 on the table 15. The edge of the part17 is beveled at 27 and a parallel beveled face is formed on a lug 29 ofthe table 15.

The operative connection between the flap 18 and the inner bracket 5 iseffected by a rod 30 which is pivotally connected wit an eye 31 of theflap 18 and the arm an angular lever by spherical knuckles and 3 1,respectively.

33 The lever 8 is fulcrumed on a pin 35 which is carried in a boss 36projecting from the lug 7 atthe base in a slotted Ll-shaped holder 4.1which is secured to the lower lug 9 of the bracket 1 by means of a clamp42 and a set screw 43. The pin 89 may be adjusted in the slot of itsbracket 11 and held in position by a knurled nut 44 or any othersuitable means.

15 is an inclined face extending along one edge of the flap 18, and 46is a straight-edge extending on the inner side of the inclined face andin parallel to the edge of the flap. A slot 47 is formed in thestraight-edge 16 and adapted to be engaged by jibs 48 and 19 on thechuck 20 in which the drill 21 held.

The chuck 20 is made up from two jaws 50 and 51 each jaw comprising aninclined face adapted to engage the inclined face 45, a stepped parallelface adapted to engage the mating face, and a f-shaped grip 52 and 53,respectively. The jaws are extended at the front ends so as to projectfrom the body of the chuck as indicated at 54 and in Fi 2. Each jaw isprovided with a pin 56 and 57, the pin of each jaw projecting through aslot 58 and 59, respectively, in the other jaw. This will appear fromFig. 2 where the pin 57 of the jaw 51 is shown projecting from the slot-58 in the jaw 50. Similarly, the pin 56 of the jaw 50 projects throughthe slot 59 in the mating jaw 51. The pins 56 and 57 are arranged at therear ends of the awe and a screw 60 is secured in the front end of thejaw 51 and engages a slot 61 in the jaw 50 so that the jaws are guidedat both ends. A spring 62 which is inserted between the jib 49 of thejaw 50 engages the jaw 51, tending to hold the jaws engaged with thedrill 21 when it has been inserted between the t -shaped parts 52 and55. A screw 63 in the jib 4.8 of the jaw 51 serves for clamping thejaWsfirmIy in the relative position which has been imparted to them, anda slot 46 is made in the straight-edge 4-6 for the head of the screw.

In the illustrated position of the chuck, the jaw 51 is resting on theinclined face and the pin 56 of the mating jaw projects into a curvedslot Get in the flap 18. A double-armed lever 65 is arranged below thepart 18 and adapted to rock about a fulcrum 66. A pin 67 is secured inthe shorter arm of the lever 65 and. projects upwards throrurh thecurvedslot 6% so as to engage the pin 56. By turning this lever on its fulcrum66 in anticlockwise direction the chuck 20 is pushed forward toward thegrinding wheel 10.

Referring now to Fig.9 this shows the method of securing the grindingwheel 10 to the shaft 68 of the pulley 11. A threaded pin 69 projectsaxially from the shaft 68 and a threaded sleeve 70 is secured on the pinand engages the frontface of the grinding wheel'with its front plate 71.An annulus 72 is seated on the threaded portion of the nea lee've 'ZOandadapted to exert axial pressure on a washer 73 which may be of lead soas to hold the grinding wheel. firmly between the parts 71 and T2.

The operation of my machine is as follows:

Supposing a drill 21 to be inserted in the chuck 20, in the positionillustrated in Fig. 4-, the chuck is placed on the faced-.5 of the flap18 so that its lower aw 51 rests on the inclined face. The chuck is heldby hand so as to engage the face of the straight-edge 4:6. The pin 56projects into the slot Gl and is engaged by the pin 67 on the lever 65.

In order to grind the drill the operator depresses the flap 1%? byrocking; it about its hinge 19. This motion causes the end of the drillto become engaged under a certain pressure with the face of thegrinding;' wheel 10. Depression of the flap 18 will impart rockinsrmotion to the inner bracket 5 through the medium of the rod 80 and theangular lever 32, 37. The angle through which the inner bracket 5 isrocked about the axis (Z in the bracket 1, is a function of the anglethrough which the flap 18 is depressed and of the ratio at which themotion of the flap 18 is transmitted to the inner bracket 5, for it willbe understood that this ratio may be varied by adjusting; the pin andbe- 1 comes 1 when the pin. 40 is placed co-aicially with the pin 85, sothat themotion of the flap 18 will not influence the inner bracket 5 atall so that the point of the drill will be ground conically by rockingthe flap 18 about the axis 0 but will not be relieved.

Relief is given to the grinding edges of the drill by rocking thebracket 5 about the'aXis (1 through the medium of the rod and the partsconnected therewith. It will be understood that by rocking the bracket 5about the axis (1. as indicated by the arrow in Fig. 4, the drill willbe rocked about'the outer end of its cutting edge and the extent towhich this is effected and which may be determined by adjusting the pin40 with respect to the pin determines the relief.

The chuck is fed toward the wheel 10 by means of the lever 65. When oneedge has been finished the chuck is reversed by placing;

the jaw on the inclined face 4-.5 of the flap 1.8., and operating asdescribed.

In order to facilitate the operation of the machine and to enable it tobe adjusted rapidly for the given size of the drill, the drill tobeground is, inserted between the inclined parallel face 27 of thesupport 17 and the corresponding face of the lug 29 at the table 15 andthe corresponding chuck is found on the graduation. Obviously the chucksfor the several sizes maybe numbered and the number of the chuckrequired for a given drill may be directly read at the graduation 28.Each chuck is so designed that the central line b of the drill is at adistance below the axis 0 of the hinge 19 which ness of the drill core,and the chisel edge will be in the proper position.

According to my invention provision is made tor e abling a given chuckto be adapted to several. or a of drills; The chuck, when the drill isinserted, will auto- "iat-Ically assume the correct position withrespect to the axis 0. This is effected by the inzlined face 15 incombination with the strtg ht-edge The position of the jaw which engages the straight-edge, that is, the jaw 50 in Fig. 7, is held in aninvariable position for any size of drill but the other jaw which is onthe inclined face 45, the jaw 51 in Fig. 7, is displaced on the facevfor a distance which is a function of the drill size that withincreasing" size of the drill the vertical distance between the axis 0and the central line 7) of the drill will increase. As the two jawsengage each other with parallel faces each drill will be in the sameposition,-as far as its cutting edges are concerned. Freferably each jawis provided with a mark an along its central plane and when the drill isinserted between the jaws of the chuck, care should be taken that itscutting edges are substantially parallel to.

the marks m.

In this manner, the same chuck may be used for drills of various sizes,within comparatively wide limits, and the number of chucks to be kept instock is reduced.

Means may be provided for varying the angle a; between the face of thegrinding wheel 10 and the central line b of the drill. This may beeffected, for instance, by dividing the lug 7 of the inner bracket 5 sothat the angular position of the bracket and the axis of the pin may bevaried. Means for this purpose are not illustrated as they will beobvious to any expert.

I wish it to be understood that I do not desire to be limited to theexact details of construction shown and described for obviousmodifications will occur to a person skilled in the art.

I claim 1. Machine for grinding spiral drills comprising a frame, agrinding wheel carried in said frame, a bracket pivotally connected tosaid frame, and adapted to rock about an axis which coincides with theface of the grinding wheel, a support for the drill to be ground securedon said bracket and comprisine; a hinged flap, the axis of said hingeextending at an angle to the face of the grindine' wheel chuck for thedrill to be ground adapted to be attached to said flap, and mechanismconnecting said hinged flap with saitv bracket so as to impart rockingmotion to said bracket when said flap is turned about its hinge. I

9,. Machine for grinding spiral drills comprising a frame, a grindingwheel carried in is at'least equal to half the hicks said frame, abracket pivotally connected to said frame, andadapted to rock about anaxis which coincides with the face of the grinding wheel, a support forthe drill to be ground secureo on said bracket and comprising a hingedflap, the axis of said hinge extending at an angle to the face of thegrinding wheel, a chuck for the drill to be ground adapted to beattached to said flap, a rod pivotally connected with said flap, arocking lever fulcrumed on said bracket and pivotally connected withsaid rod and a pin connected with said frame and engaging said lever soas to form its stationary fulcrum.

3. Machine for grinding spiral drills coinprlsing a frame, a grindingwheel carried in said frame, a bracket pivotally connected to saidframe, and adapted to rock about an axis which coincides with the faceof the grinding wheel, a support for the drill to be ground secured onsaid bracket and comprisii'ig a hinged flap, the axis of said hingeextending at an angle to the face of the grinding wheel, a chuck for thedrill to be ground adapted to be attached to said flap, a rod pivotallyconnected with said flap, a

rocking lever fulcrumed on said bracket and pivotally connected withsaid rod, a pin connected with said frame and engaging said lever so asto form its stationary fulcrum, and means for varying the position ofsaid pin with regard to the fulcrum of the lever on said bracket.

lifachine for grinding spiral drills comprising frame, a grinding wheelcarried in said frame, a bracket fulcrumed on said frame, a bracketpivotally carried in said first-mentioned bracket so as to rock about anaxis which coincides with the face of the grinding wheel, a support forthe drill to be ground secured on said second-mentioned bracket andcomprising a hinged flap, the axis of said hinge extending at an angleto the face of the grinding wheel, a chuck for the drill to be groundadapted to be attached to said flap, and mechanism connecting saidhinged flap with said first-mentioncd bracket so as to impart rockingmotion to said first-mentioned bracket when said iia; is turned aboutits hinge.

tee mony whereof I affix my signature.

ALEXANDER ZiiHRINGER.

